/*
   Copyright (c) 2011, 2012 Mizar Tools Contributors (mizartools.org)

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/
/*  Contributors :
 *	2011-02-18 Marco Riccardi - initial implementation
 *  2012-04-06 Marco Riccardi - added message in DliParseException
 *
 */
package org.mizartools.dli;

public class Iff extends Formula {

	private Formula formula1 = null;
	private Formula formula2 = null;
	
	public static Iff newInstance(String string) throws DliParseException {
		Iff implies = new Iff();
		int position = Utility.searchSeparationComma(string);
		if (position == -1) {
			throw new DliParseException("["+string+"] is not valid in Iff");
		}
		implies.formula1 = Formula.newInstance(string.substring(0, position));
		implies.formula2 = Formula.newInstance(string.substring(position+1));
		return implies;
	}
	
	private Iff(){
		super();
	}
	
	public Iff(Formula formula1, Formula formula2) throws DliException {
		if (formula1 == null || formula2 == null){
			throw new DliException();
		}
		this.formula1 = formula1;
		this.formula2 = formula2;
    }
	
	@Override
	public String toString() {
		return "$iff("+formula1.toString()+","+formula2.toString()+")";
	}

	public Formula getFormula1() {
		return formula1;
	}

	public Formula getFormula2() {
		return formula2;
	}
	
}
